Effects of ANT, APS, and GPS on serum diamine oxidase (DAO) (A) and D-lactic acid (D-LA) (B) level in broilers. Data are means ± SEM, n = 6. Means with different letters indicate significant difference (P < 0.05). Abbreviations: ANT, basal diet supplemented with 500 mg/kg terramycin calcium; APS, basal diet supplemented with 300 mg/kg Astragalus membranaceus polysaccharides; CON, control group with basal diet; GPS, basal diet supplemented with 150 mg/kg Glycyrrhiza uralensis polysaccharides.